NHLBI is providing support to HIV-related research activities within the FDA-led U.S. Transfusion-Transmissible Infections Monitoring System (TTIMS). The project will include characterization of transfusion-transmissible infection marker risks in the U.S. blood supply with monitoring of temporal, geographic, and demographic trends, will provide a framework for evaluating the effect of new interventions on transfusion-transmissible infection risks and blood donor risk factors. The project will also establish a framework for evaluation of newly emergent or re-emergent infectious diseases of concern to the blood supply.